drawback

Today there is a customer that had a database error, let me see. Error: 1601, Severity: 17, State: 3 There are not enough 'user connections' available to start a new process. Retry when there are fewer active users, or ask your System Administrator t

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First check D: \ oracle \ product \ 10.1.0 \ Db_1 \ NETWORK \ ADMIN in the tnsnames.ora file. Has the following configuration files ORCL = / / can take the individual to the database instance name for PL-SQL in the log when the value selected in the

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Am finally out of the environment in which to spend the linux fcitx the English. Take a lot of costly mistakes. Why do we have in English environment? Chinese environments fcitx or sicm are very easy thing, installed ready for use. But the Chinese en

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For the select, poll, epoll know not by much, the following is from "Building high-performance Web site" excerpt introduction, and so after the real exposure to select, poll and epoll write in detail about the development of the use of the diffe

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1 install a digital certificate Execute java InstallCert test.ldh.com: 443 Download digital certificate, InstallCert.java Annex, test.ldh.com you tune into the interface of the domain name, the certificate only needs the next time the machine can be

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Because business needs, repair to modify a field data types are number (5), into a number (5,2)-type If no data, then the following statements can be directly alter table tb_test modify permile number (5,2); But data can not be used if the above meth

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Database indexes to increase query speed and additional fields in a table identifier. Many people understand the concept of indexing machinery, that an increase in the index can only be good. In fact, as far here as much detail as some of its introdu

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ConcurrentHashMap and CopyOnWriteArrayList comparison. Blog categories: Java ConcurrentHashMap ConcurrentHashMap introduced Segment, each Segment is a hashtable, the equivalent of two Hash table, and then lock in the Segment level, and increased conc

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Slackware version: Slackware 7.0 and above Slackware uses BSD-style init script, and many other distributions use System V style init scripts. SysV and BSD scripts are able to make people read, that they are shell scripts, not compiled program. The m

parameters, bind, many things, squeeze, startup script, shell scripts, drawback, script execution, symbolic link, distributions, startup scripts, script design, style scriptSeptember 7

23 commonly used in Java Design Patterns 1, the factory pattern: separate customer classes and factory class. Consumers need a product at any time, simply a request to the factory. Consumers can not modify the admission of new products. The disadvant

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1 Why should I use LVM In LVM, before the system administrator (referred to as SA) should be aware that although traditional disk management has played good enough to use fdisk can directly create, delete partitions, but the traditional disk manageme

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PCTUSED parameters: When the actual data block (block header information and datas data) occupies the space below the set value will be added to the freelist. For example, PCTUSED = 40. However, deleting data, the remaining space is greater than (1-4

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Select the cloud: shop around 2011-8-15 Author: David Strom Translator: Liang Yingzong Source: TechTarget to China I want to comment Share: Digg This English-language blog references | Medium | Small REVIEW: This article covers the Amazon, Verizon, G

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1 Chinese-style Dashboard Chinese-style reporting and Dashboard have a lot of similar place. Mainly used to display summary data. Most appear in the page (screen), closely arranged. Used to make a quick comparison of data and scanning. The biggest di

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Tried to use scp for file transfers, this command is better, not the machine or what services are installed on the client machine, but has a drawback, the need to manually enter the password I set on the server had a plan A, weekly a copy command, th

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Within the department to implement code review in this activity a few months ago started looking for tools to support the beginning of this phase is jupiter eclipse plug-in the beginning also wrote a user guide (see annex), but later I found It is cl

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This article comes from: http://hi.baidu.com/suofang/blog/item/e45d5a4e883e9e07b3de0519.html Is to generate a GUID it? SQL> select sys_guid () from dual; SYS_GUID () -------------------------------- F18031C69D8345DEB305D4B2E796A282 You can put a tabl

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Blog: obsolete or irreplaceable? More than a decade since the advent of blog, this was once considered the most influential web2.0 new media now seems to gradually lose its irreplaceable position. With SNS, micro-blog, and so the emergence of new onl

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Virtual machine through the host computer in several ways: 1, Bridged (bridge) mode, if the host is through the LAN access the Internet, allows the virtual machine using the host network segment, the same gateway and DNS settings, use a valid LAN IP.

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Third, the development stage First, the configuration management tool There are a lot of code management tools, and now the company with more than code management tools CVS, VSS, SVN. For a team is only 2-5 individuals, and this is the same office tw

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Official module description: http://wiki.nginx.org/HttpUpstreamModule http://www.howtocn.org/nginx:Nginx% E6% A8% A1% E5% 9D% 97% E5% 8F% 82% E8% 80% 83% E6% 89% 8B% E5% 86% 8C% E4% B8% AD% E6% 96% 87% E7% 89% 88 Talk about the upstream in the server

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Optimistic locking and pessimistic locking is the corresponding, so to talk about optimistic locking, it is inevitable to talk about what is pessimistic locking, optimistic locking is what? The so-called pessimistic locking is that the query after th

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tmp_table_size If the in-memory temporary table exceeds this value, MySQL automatically converts it to the hard disk MyISAM table. If you perform many advanced GROUP BY queries and there are a lot of memory, you can increase the value of tmp_table_si

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http://blog.csdn.net/tianlesoftware/archive/2009/10/15/4677378.aspx http://ajava.org/readbook/db/oracle11gjctg/5762.html In Oracle 10g which, is the introduction of flashback version query, flashback transaction query, flashback database, flashback t

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Requirements: Required database objects (eg: Table, Trigger, View, Function, StoredProcedure, etc.) to migrate to the same database server or a remote database server, and renamed required to support migration, and migration of certain objects can be

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The model was to address resource allocation ﹑ frequent problems caused by the release. To address these problems, you can use database connection pool. The basic idea of ​​the database connection pool is to establish a database connection "pool.&quo

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TokyoTyrant MemcacheDB TreapDB Redis LightCloud Berkeley DB MongoDB Cassandra Voldemort First, read and write performance to meet the high demand for Key-Value Database Key-Value performance of the main features of the database is a highly concurrent

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offers three advanced backup oracle advanced replication (Advanced Replication) Stream replication (Streams Replication) Prepared by the library (Dataguard) A dataguard: high availability and disaster recovery in terms dataguard generally dba choice,

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Sometimes, this thing can omit a lot of things ~ INSERT INTO table (column_a, column_b, column_c) VALUES (1, 2, 3) ON DUPLICATE KEY UPDATE column_c = column_c + 1; A better way to add or update MySQL rows Recently, we needed to iterate over a fairly

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1. Avoid hard parsing - use a prepared statement (JDBC in use PreparedStatement) (2) avoid soft parse - reuse the prepared statement (JDBC PreparedStatement in the run does not close after next check occasionally also the object database) 3 The clien

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1, if the field is simply a big change, such as numeric (16,2 )---> numeric (16,4), can be directly alter table table name modify (field name numeric (16,4) 2, due to changes in demand, now to a type NUMBER (8,2) field types to char. General idea is

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GROUP BY clause there is a drawback, is that the returned result set only aggregate data, without detailed records of the original. If you want to do this in SQL SERVER, you can use the COMPUTE BY clause. COMPTE generate a summary of the total listed

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PERCONA PERFORMANCE CONFERENCE 2009, and several engineers from Yahoo, brought an " Efficient Pagination Using MySQL "report, there are many bright spots, this article is based on the further extension of the original. First look at the pages of

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Introduction: Before the downpour with a paste (http://www.iteye.com/topic/143714) discusses how to use mysql in java the master-slave mode (master-slave mode description, see Qieqie this paste: http:// www.iteye.com/topic/162717), which greatly that

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Simple needs analysis: 1 to achieve unlimited classification. 2 for unlimited level navigation links 3 to achieve progressively classified information under various inquiries, including the most page views, up to comment on the amount of the latest i

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Turn http://hi.baidu.com/wschao2005/blog/item/fe037089d5a18eb80e2444ad.html High Water Mark (HWM) means that when we build a segment of time, an indicator within the segment, defining the segment has been configured within the block level. Segment ha

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Determine success of the project's core role? I consider the three roles: project manager, technical manager and demand manager. Project Manager: how to solve management problems, the progress of the project and responsible for the quality. Specific

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Because there is a demand to study the next redis, a high-performance of key-value database. Here the record about it, need it to prepare for follow-up time has also brought to share with you. Redis is essentially a type of Key-Value-memory database,

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Tangle of the place; a latitude of 7, the other a latitude is 7, but have a duplication; collection of latitude is 100 +, but also too much, two have? How to integrate it; full join; that you can take advantage of are taken out; weight after 7 to 8 +

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Others written in SQL to improve the efficiency of a good summary of the method, very practical, down In the massive data tables, each table has a basic or more indexes to ensure efficient query, the index during the ETL process needs to use the foll

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1: index, our first thought is to create an index, an index can be multiplied to create a query to enhance efficiency and save time. However, if the data is too great amount of time, this time simply to create the index is useless, we know that if a

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Oracle Dataguard provides three data protection modes, respectively, to sum ​​up in three data protection mode features. 1. Maximum protection mode 1) This mode provides the highest level of data protection; 2) requires at least one physical standby

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Promote software progress in the end? It is said that the software they are big lazy cow, because lazy and invent new things, so we too lazy to benefit, too lazy to bear fruit. Also said to be enthusiastic, passionate or something? Sound is not too p

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First, an overview I believe a lot of people often ask the same question: When MySQL The total number of records more than 100 million later, there will be a significant decline in the performance of it? The answer is yes, but the performance> of the

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EXISTS, IN and JOIN Performance Analysis EXISTS, IN and JOIN, can be used to achieve the form "A table in the query (or not) B records in the table," the query logic. In the forum to see a lot of people are misunderstanding (such as in the doubt

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Database indexes to increase query speed and added a field to the table identifier. Have seen many people understand the concept of indexing machinery, that an increase in the index can only be good. This study notes the index before trying to sum up

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http://www.bitscn.com/pdb/oracle/200810/152282.html A: sql loader features oracle himself with a lot of tools can be used for data migration, backup and recovery work. But each tool has its own characteristics. For example, exp and imp data in the da

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sql loader can store some data in text format smoothly into the oracle database, is a kind of data migration between different databases is very convenient and versatile tool. Drawback is slow, the other types of data on the blob so little trouble. s

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imp import data specified table space, roughly the following ways: 1. There is a simple method for the data relatively few cases: the direct use UltraEdit to fight side DMP file, the default is hexadecimal, switch to text mode, the inside: TABLESPACE

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Today in the All Programs menu option to enter the oracle, suddenly can not find it on their own ways to do one, just create a bat file, enter the command: F: \ oracle \ ora92 \ bin \ oemapp.bat console One path can be changed to your own oracle inst

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